1. Field of the Invention
The present invention relates to an internal combustion engine and in particular to an engine timing gear cover having integral coolant flow passages.
2. Description of Related Art
The timing gear cover of the present invention is bolted to one end face of a cylinder block and provides a cover for the timing gear. The timing gear is disposed in a timing gear chamber that is formed by the face of the cylinder block and the timing gear cover. The timing gear cover is further formed with integral fittings for coupling the timing gear cover to a radiator for both discharging coolant to the radiator as well as receiving coolant from the radiator. The timing gear cover defines a water pump inlet chamber connected to the inlet coolant fitting that receives coolant from the radiator. The timing gear cover also forms a water pump outlet chamber that receives coolant from the water pump. The water pump outlet chamber communicates with a coolant inlet in the cylinder block for directing the coolant to the block. Coolant flows through the cylinder block and to the cylinder head in a known fashion and is discharged from the cylinder head to a hot coolant chamber also integrally formed in the timing gear cover. The hot coolant chamber communicates with the discharge coolant fitting in the cover for discharge of the coolant to the radiator. The discharge coolant fitting also houses the thermostat.
The timing gear cover is bolted to the cylinder block and is not bolted to the cylinder head. Accordingly, a resilient seal is placed between the cylinder head and timing gear cover to ensure a leak proof coupling therebetween.
The water pump is mounted to the front of the timing gear cover. The water pump receives coolant through an opening in the timing gear cover to the water pump inlet chamber. The outlet of the water pump is directed through another opening in the timing gear cover to the water pump outlet chamber for flow of coolant to the cylinder block.
The timing gear cover also includes a coolant bypass from the hot coolant chamber to the pump inlet chamber to allow coolant circulation through the engine prior to the thermostat opening. A novel aspect of the timing gear cover is the placement of the water pump inlet chamber between the water pump outlet chamber and the timing gear chamber. As a result, any leak of coolant from the higher-pressure water pump outlet chamber will flow into the lower pressure water pump inlet chamber. The coolant does not flow into the timing gear chamber where the coolant would contaminate the engine lubricating oil. This arrangement of the coolant chambers in the timing gear cover improves the reliability of the engine by eliminating or minimizing the likelihood of coolant leaks into the lubricating oil.
The integration of the thermostat housing into the timing gear cover with an integral bypass is another novel aspect of the invention.